GP Lenses (Gas Permeable)
Gas Permeable contacts, sometimes called GP lenses, Rigid Gas Permeable lenses or RGP lenses, are crafted out of compounds containing silicone. The lenses are hard, but they allow for oxygen to move through them and reach the surface of the eye, thereby allowing the eyes “breathing room.” These lenses have several advantages when directly compared to their soft counterparts.
GP Lenses – Advantages
As mentioned above, GP lenses breathe and thereby give access to oxygen so it can come in contact with the eye’s surface. Since oxygen can get to the eye, there is a decreased chance of having issues with hypoxia. The latter condition involves a reduction in the amount of oxygen supplied to the eye. GP lenses allow for a greater oxygen supply when compared to soft contacts. The lens’s silicone containing compound alloys for a greater degree of oxygen to get through the lens. Many soft lenses are made of silicone hydrogel materials. GP lenses allows for better transmission of oxygen.
GP lenses have diameters that are actually smaller than soft lenses, and do not cover up a large space on the eye’s surface. When you are wearing GP lenses, they move whenever you blink and maintain the appropriate shape when in your eye. The movement allows for the lens to push oxygenated tears up beneath the lens and between the lens and the surface of the eye. With soft lenses, the move little when blinking, so tears do not transmit between the lens and the eye like GP lenses allow. The lens of soft contacts fit to the cornea.
You get sharper visual acuity when wearing GP lenses. The lenses are well shaped and ultra smooth allows for greater vision. In contrast, soft lenses may dry out and lose flexibility and/or shape, so the vision is not as sharp for the user. Finally, GP lenses are excellent for astigmatism and prove more stable in dealing with the irregular shape of the eye.
Soft lenses are so flexible that they tear and rip with ease: this is not the case with GP contacts because of their rigid formation. Soft lenses require frequent replacement whereas GP lenses do not – you can use GP lenses for up to a year or even longer in some cases. Due to their durability, GP lenses are economical as well.
If you are nearsighted, gas permeable lenses may help you in dealing with the condition, and it can even hinder the condition’s progression. The latter fact is particularly true in children. Gas permeable lenses are also part of Orthokeratology treatments, where a person uses special contacts to sleep in at night and remove during the day. The lenses reshape one’s cornea, at least temporarily, and thereby improve vision.
So, are there any disadvantages of using gas permeable lenses?
GP Lenses – Disadvantages
Wearing gas permeable lenses takes some time to get used to; it may be a few weeks before you feel comfortable while wearing the lenses. You will start out wearing the lenses for a few hours every day and work your way up to wearing them for an entire day. It gives your eyes time to adjust. Some individuals who have worn soft lenses in the past and then convert to wearing GP lenses find a preference for GP contacts because they prove more comfortable and offer sharper vision.
GP lenses require you wear them every single day so you can adjust to their use. If you cease using the lenses, you may have to go through a period of re-adaptation. During that time, you become more aware of the fact that you have lenses on your eyes and it can prove distracting and uncomfortable.
GP lenses may become dislodged with greater ease. The fact that the lenses cover a smaller area on the surface of the eye makes it easier to lose a lens – this is true if you are rubbing your eye or even when playing sports.
When you use GP lenses they are vulnerable to dust, debris, and sand and these particles can get between the lens and they where they can cause considerable irritation. Thus, GP lenses may not be ideal for people who spend a lot of time along the beach. The lenses can prove uncomfortable on windy days, and you may have to wear wrap style sunglasses whenever you are outdoors to protect your eyes from irritants.
If you lose GP lenses, you will pay a considerable cost to replace them. Soft lenses are available in a few limited sizes, but GP contacts are actually customized to fit the actual shape of the eye. The customization of size and shape increases the cost of GP contacts and their replacement. Further, when in need of replacement lens, you may have to wait seven days or more to get them: This means you should invest in a spare pair in case of emergency, and this is an additional expense.
Hybrid Lens – The Best of Everything
Hybrid lenses are an exciting innovation where you get lenses featuring a gas permeable center and a soft peripheral edge or skirt. This means you get the comfort of wearing soft contact lenses all while getting the sharp vision that comes with GP contacts.